[PEI] Don't zero out noreg operands
A tail call may have $noreg operands.
Fixes a crash.
Reviewed By: xgupta
Differential Revision: https://reviews.llvm.org/D156485
This should fix an assertion failure building qemu, specifically those
parts using -fzero-call-used-regs.
Reported by: Daniel Berrangé <dan-freebsd@berrange.com>
PR: 277474
MFC after: 3 days